Butler: This tool makes it easy to perform different, potentially recurring, tasks. For example, launch certain apps with keyboard shortcuts; add new menus; run scripts with a certain mouse click. When you start using it, you’ll wonder how you lived without it! Some example I frequently use are:

Cost: Free trial; $20 to buy (totally worth it). Note that the developers Peter and Rob donate most of their proceeds to charity.

Notes

the settings file can be found at /Users/your home directory/Library/Preferences/com.hegenberg.BetterTouchTool.plist . This is useful for exporting settings from one machine to another. It can even be out under source control.

I always like to disable the control-space shortcut that Butler uses by default (for “Enter abbreviation…”) since I use that shortcut elsewhere.

Screenshots: I find the Grab tool invaluable for taking screenshots. You can also take screenshots using just keyboard shortcuts but I find Grab very intuitive to use.

Cost: Free (included with Mac)

Bookmarks: Sharing bookmarks across machines is always useful. I now use Chrome synch. In the past, I used to use XMarks, which has now been shutdown.

Image Editing: While Macs do come with free text editing software (e.g. TextEdit), they surprisingly do not come with even basic image editing. PaintBrush fills this gap. A free app that is similar to Windows Paint, and useful for basic editing such as cropping and resizing of images.

Cost: Free!

Vimium: Vimium is a Google Chrome extension which provides keyboard shortcuts for navigation. Great if you prefer keyboard over mouse.